BOCK FORMATIONS. 1C5 



nd to euphotides, analogous to those I found in the moun- 

 tains of Guanabacoa. 



The central and western parts of the island contain two 

 formations of compact limestone ; one of clayey sandstone, 

 and another of gypsum. The former has, in its aspect and 

 composition, some resemblance to the Jura formation. It 

 is white, or of a clear ochre-yellow, with a dull fracture, 

 sometimes conchoidal, sometimes smooth ; divided into thin 

 layers, furnishing some balls of pyromac silex, often hollow, 

 (at Rio Canimar, two leagues east of Matanzas), and petri- 

 fications of pecten, cardites, terebratules, and madrepores.* 

 I found no oolitic beds, but porous beds almost bulbous, 

 between the Potrero del Conde de Mopox, and the port of 

 Batabano, resembling the spongy beds of Jura limestone in 

 Franconia, near Dondorf, Pegnitz, and Tumbach. Yellowish 

 cavernous strata, with cavities from three to four inches in 

 diameter, alternate with strata altogether compact, f and 

 poorer in petrifications. The chain of hills that borders the 

 plain of Guines on the north, and is linked with the Lomas 

 de Camua. and the Tetas de Managua, belongs to the latter 

 variety, which is reddish white, and almost of lithographic 

 nature, like the Jura limestone of Pappenheim. The com- 

 pact and cavernous beds contain nests of brown ochreous 

 iron; possibly the red earth (tierra colorada) so much 

 sought for by the coffee planters (haciendados) owes its 

 origin to the decomposition of some superficial beds of 

 oxidated iron, mixed with silex and clay, or to a reddish 

 sandstone^ superposed on limestone. The whole of this 

 formation, which I shall designate by the name of the lime- 

 stone of Guines, to distinguish it from another much more 

 rrrent, forms, near Trinidad, in the Lomas of St- Juan, 

 steep declivities, resembling the mountains of limestone *>f 

 Cai ipe, in the vicinity of Cumana. They also contain great 

 us, near Matanzas and Jaruco, where I have not heard 

 that any fossil bones have been found. The frequency of 



* I saw neither gryphite*, nor ammonites of Jura limestone, nor the 

 unimulites and cerites of coarse limestone. 



t The western part of the island has no deep ravines ; and we recopnizc 

 thi* alternation in travelling from the Havannah to Batabano, the deepest 

 beds (inclined from 30 to 40 N.E.) appear as we advance. 



t iauditone and ferruginous saud; iron-sand? 



